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[2026-06 LWG Motion 15] P3772R2 std::simd overloads for bit permutations #9116

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[2026-06 LWG Motion 15] P3772R2 std::simd overloads for bit permutations #9116

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109 changes: 109 additions & 0 deletions source/numerics.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -17385,6 +17385,7 @@

// \ref{simd.bit}, bit manipulation
template<@\exposconcept{simd-vec-type}@ V> constexpr V byteswap(const V& v) noexcept;
template<@\exposconcept{simd-integral}@ V> constexpr V bit_reverse(const V& v) noexcept;
template<@\exposconcept{simd-vec-type}@ V> constexpr V bit_ceil(const V& v);
template<@\exposconcept{simd-vec-type}@ V> constexpr V bit_floor(const V& v) noexcept;

Expand All @@ -17401,6 +17402,11 @@
template<@\exposconcept{simd-vec-type}@ V>
constexpr V rotr(const V& v, int s) noexcept;

template<@\exposconcept{simd-integral}@ V0, @\exposconcept{simd-integral}@ V1>
constexpr V0 bit_repeat(const V0& v, const V1& l);
template<@\exposconcept{simd-integral}@ V>
constexpr V bit_repeat(const V& v, int l);

template<@\exposconcept{simd-vec-type}@ V>
constexpr rebind_t<make_signed_t<typename V::value_type>, V>
bit_width(const V& v) noexcept;
Expand All @@ -17420,6 +17426,16 @@
constexpr rebind_t<make_signed_t<typename V::value_type>, V>
popcount(const V& v) noexcept;

template<@\exposconcept{simd-integral}@ V>
constexpr V bit_compress(const V& v, const V& m) noexcept;
template<@\exposconcept{simd-integral}@ V>
constexpr V bit_expand(const V& v, const V& m) noexcept;

template<@\exposconcept{simd-integral}@ V>
constexpr V bit_compress(const V& v, typename V::value_type m) noexcept;
template<@\exposconcept{simd-integral}@ V>
constexpr V bit_expand(const V& v, typename V::value_type m) noexcept;

// \ref{simd.complex.math}, complex math
template<@\exposconcept{simd-complex}@ V>
constexpr rebind_t<@\exposid{simd-complex-value-type<V>}@, V> real(const V&) noexcept;
Expand Down Expand Up @@ -17591,15 +17607,19 @@
using simd::byteswap;
using simd::bit_ceil;
using simd::bit_floor;
using simd::bit_reverse;
using simd::has_single_bit;
using simd::rotl;
using simd::rotr;
using simd::bit_repeat;
using simd::bit_width;
using simd::countl_zero;
using simd::countl_one;
using simd::countr_zero;
using simd::countr_one;
using simd::popcount;
using simd::bit_compress;
using simd::bit_expand;

// See \ref{simd.complex.math}, \tcode{vec} complex math
using simd::real;
Expand Down Expand Up @@ -20575,6 +20595,23 @@
\range{0}{V::size()}.
\end{itemdescr}

\indexlibrarymember{bit_reverse}{simd}
\begin{itemdecl}
template<@\exposconcept{simd-integral}@ V> constexpr V bit_reverse(const V& v) noexcept;
\end{itemdecl}

\begin{itemdescr}
\pnum
\constraints
The type \tcode{V::value_type} is an unsigned integer type\iref{basic.fundamental}.

\pnum
\returns
A \tcode{basic_vec} object where the $i^\text{th}$ element is initialized to
the result of \tcode{std::bit_reverse(v[$i$])} for all $i$ in the range
\range{0}{V::size()}.
\end{itemdescr}

\indexlibrarymember{bit_ceil}{simd}
\begin{itemdecl}
template<@\exposconcept{simd-vec-type}@ V> constexpr V bit_ceil(const V& v);
Expand Down Expand Up @@ -20640,11 +20677,14 @@

\indexlibrarymember{rotl}{simd}
\indexlibrarymember{rotr}{simd}
\indexlibrarymember{bit_repeat}{simd}
\begin{itemdecl}
template<@\exposconcept{simd-vec-type}@ V0, @\exposconcept{simd-vec-type}@ V1>
constexpr V0 rotl(const V0& v0, const V1& v1) noexcept;
template<@\exposconcept{simd-vec-type}@ V0, @\exposconcept{simd-vec-type}@ V1>
constexpr V0 rotr(const V0& v0, const V1& v1) noexcept;
template<@\exposconcept{simd-integral}@ V0, @\exposconcept{simd-integral}@ V1>
constexpr V0 bit_repeat(const V0& v0, const V1& v1);
\end{itemdecl}

\begin{itemdescr}
Expand All @@ -20661,32 +20701,55 @@
\tcode{sizeof(typename V0::value_type) == sizeof(typename V1::value_type)} is \tcode{true}.
\end{itemize}

\pnum
\expects
For \tcode{bit_repeat},
\tcode{v1[$i$] > 0} is \tcode{true}
for all $i$ in the range \range{0}{V0::size()}.

\pnum
\returns
A \tcode{basic_vec} object where the $i^\text{th}$ element is initialized to
the result of \tcode{\placeholder{bit-func}(v0[$i$],
static_cast<int>(v1[$i$]))} for all $i$ in the range \range{0}{V0::size()},
where \tcode{\placeholder{bit-func}} is the corresponding scalar function from \libheader{bit}.

\pnum
\remarks
A function call expression that violates the precondition in the \expects
element is not a core constant expression\iref{expr.const.core}.
\end{itemdescr}

\indexlibrarymember{rotl}{simd}
\indexlibrarymember{rotr}{simd}
\indexlibrarymember{bit_repeat}{simd}
\begin{itemdecl}
template<@\exposconcept{simd-vec-type}@ V> constexpr V rotl(const V& v, int s) noexcept;
template<@\exposconcept{simd-vec-type}@ V> constexpr V rotr(const V& v, int s) noexcept;
template<@\exposconcept{simd-integral}@ V> constexpr V bit_repeat(const V& v, int l);
\end{itemdecl}

\begin{itemdescr}
\pnum
\constraints
The type \tcode{V::value_type} is an unsigned integer type\iref{basic.fundamental}.

\pnum
\expects
For \tcode{bit_repeat},
\tcode{l > 0} is \tcode{true}.

\pnum
\returns
A \tcode{basic_vec} object where the $i^\text{th}$ element is initialized to
the result of \tcode{\placeholder{bit-func}(v[$i$], s)} for all $i$ in the
range \range{0}{V::size()}, where \tcode{\placeholder{bit-func}} is the corresponding
scalar function from \libheader{bit}.

\pnum
\remarks
A function call expression that violates the precondition in the \expects
element is not a core constant expression\iref{expr.const.core}.
\end{itemdescr}

\indexlibrarymember{bit_width}{simd}
Expand Down Expand Up @@ -20723,6 +20786,52 @@
function from \libheader{bit}.
\end{itemdescr}

\indexlibrarymember{bit_compress}{simd}
\indexlibrarymember{bit_expand}{simd}
\begin{itemdecl}
template<@\exposconcept{simd-integral}@ V>
constexpr V bit_compress(const V& v, const V& m) noexcept;
template<@\exposconcept{simd-integral}@ V>
constexpr V bit_expand(const V& v, const V& m) noexcept;
\end{itemdecl}

\begin{itemdescr}
\pnum
\constraints
The type \tcode{V::value_type} is an unsigned integer type\iref{basic.fundamental}.

\pnum
\returns
A \tcode{basic_vec} object where the $i^\text{th}$ element is initialized to
the result of \tcode{\placeholder{bit-func}(v[$i$], m[$i$])}
for all $i$ in the range \range{0}{V::size()},
where \tcode{\placeholder{bit-func}} is the corresponding
scalar function from \libheader{bit}.
\end{itemdescr}

\indexlibrarymember{bit_compress}{simd}
\indexlibrarymember{bit_expand}{simd}
\begin{itemdecl}
template<@\exposconcept{simd-integral}@ V>
constexpr V bit_compress(const V& v, typename V::value_type m) noexcept;
template<@\exposconcept{simd-integral}@ V>
constexpr V bit_expand(const V& v, typename V::value_type m) noexcept;
\end{itemdecl}

\begin{itemdescr}
\pnum
\constraints
The type \tcode{V::value_type} is an unsigned integer type\iref{basic.fundamental}.

\pnum
\returns
A \tcode{basic_vec} object where the $i^\text{th}$ element is initialized to
the result of \tcode{\placeholder{bit-func}(v[$i$], m)}
for all $i$ in the range \range{0}{V::size()},
where \tcode{\placeholder{bit-func}} is the corresponding
scalar function from \libheader{bit}.
\end{itemdescr}

\rSec3[simd.complex.math]{Complex math}

\indexlibrarymember{real}{simd}
Expand Down
1 change: 1 addition & 0 deletions source/support.tex
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Original file line number Diff line number Diff line change
Expand Up @@ -839,6 +839,7 @@
#define @\defnlibxname{cpp_lib_shift}@ 202202L // also in \libheader{algorithm}
#define @\defnlibxname{cpp_lib_simd}@ 202603L // also in \libheader{simd}
#define @\defnlibxname{cpp_lib_simd_complex}@ 202502L // also in \libheader{simd}
#define @\defnlibxname{cpp_lib_simd_bitops}@ 202606L // also in \libheader{simd}
#define @\defnlibxname{cpp_lib_simd_permutations}@ 202506L // also in \libheader{simd}
#define @\defnlibxname{cpp_lib_smart_ptr_for_overwrite}@ 202002L // also in \libheader{memory}
#define @\defnlibxname{cpp_lib_smart_ptr_owner_equality}@ 202306L // also in \libheader{memory}
Expand Down
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